3 visuals for webpage
This code will help produce the three visuals that are going to be a
part of each equity tracker indicator webpage: regional map (tract
level) of most recent data, chart of the most recent data, chart of
trends over time.
If the indicator is available through a tract-level data
set. Getting the data to a workable version may require some
data transformation. To explore, clean, transform, and generate a final
data set, please use the data-gen-tract-template. This script
will generate an .rda for the map and an .rda for the charts. These data
sets will be loaded in before the data visualization code.
Indicator Explanation
Average percentage of tree canopy by census tract. Understanding tree
canopy coverage can help us understand which communities are
disproportionately impacted by less tree canopy. Reduced tree canopy can
impact quality of life in various ways including leading to warmer
temperatures and decreased access to open space/parks.
Calculations were made using original data from MRLC
and applying ArcGIS Zonal Statistics as Table tool to calculate the
average percentage of canopy cover per census tract.
1. Map of most recent data
To map data in this form, there should be a value corresponding to
each census tract. Depending on the year or source of the data, this
could be about 700 rows for data at the 2010 census tract resolution, or
about 900 rows for data at the 2020 census tract resolution.
Create Visual
Source(s): USDA Forest Service and MRLC, Tree Canopy, 2021; U.S.
Census Bureau, Geography Division 2020 TIGER/Line Shapefiles
Data call outs
- 54%: The region’s average tree canopy coverage per census tract in
2021
- 73%: census tract with the highest average percentage of tree canopy
in 2021
- 1%: census tract with the lowest average percentage of tree canopy
in 2021
Insights & Analysis
- The census tracts with the highest average tree canopy cover
includes three census tracts in King County that include the tract east
of Enumclaw heading into the foothills of the Cascades (73%), the tract
with the Cedar River Watershed (72%), the tract with Tiger Mountain
(70%), and in Snohomish County the tract with Mt. Pilchuck (68%)
- The census tracts with the lowest average tree canopy cover are in
King County and include South Lake Union (1%), the two tracts that make
up downtown Seattle (both 1%), and the tract with Boeing Field (2%)
- King County has the highest average tree canopy cover (55.9%),
followed by Snohomish (55.8%), Kitsap (54.1%), and Pierce (50.6%)
2. Facet of most recent data
Create Visual
Tree Canopy Cover by Community
Average percent of area with tree canopy
USDA Forest Service and MRLC, Tree Canopy, 2021; U.S. Census Bureau,
2016-2021 American Community Survey 5-Year Estimates, Tables B02001,
C17002, B22010, B11005, B11007, C16002
Data call outs
- 2x: As a region, communities with low concentrations of households
with lower income have over twice the canopy cover as communities with
high concentrations
- 2x: As a region, communities with low concentrations of people of
color have over twice the canopy cover as communities with high
concentrations
- 2x: As a region, communities with low concentrations of people of
households with limited English proficiency have over twice the canopy
cover as communities with high concentrations
Insights & Analysis
- Communities with the highest concentration of people of color,
households with lower income, households with limited English
proficiency, and youth under 18 are most disproportionately impacted by
lower average tree canopy cover
- The counties with the largest gap between low and high
concentrations of people of color are King and Snohomish counties
- The counties with the largest gap between low and high
concentrations of households with lower income are King and Pierce
counties
3. Facet of trend data
Create Visual
Tree Canopy Cover Trend by Community
Average percent of area with tree canopy, in 5-year spans between 2011
and 2021
USDA Forest Service and MRLC, Tree Canopy, 2011, 2016, 2021; U.S. Census
Bureau, 2007-2011, 2012-2016, 2017-2021 American Community Survey 5-Year
Estimates, Tables B02001, C17002, B22010, B11005, B11007, C16002
Data call outs
- 50% decrease: As a region since 2016, communities with high
concentrations of households with lower income have seen over a 50%
decrease in average tree canopy coverage
- 10%: As a region, communities with high concentrations of households
with youth under 18 have seen a 10% decrease in average tree canopy
coverage since 2011
- 20%: Kitsap County has seen a 20% increase in tree canopy coverage
for households with limited English proficiency since 2011
Insights & Analysis
- As a region, communities with the highest and lowest concentrations
of people of color have seen consistent average tree canopy coverage
from 2011 to 2021
- As a region, communities with high concentrations of households with
limited English proficiency have seen consistent average tree canopy
coverage from 2011 to 2021
- Pierce County has seen the largest increase in the gap between the
highest and lowest concentrations for households with lower income
between 2011 and 2021